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Glitch when installing carbon fiber prop lost post

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Old 03-03-2008, 08:10 PM
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flynut007
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Default Glitch when installing carbon fiber prop lost post

I understand alot of post from members has gotten lost today from RCU being down....he had a problem with his airplane went into fail safe mode when he changed from a wood prop to carbon fiber when the plane coming towards him....I got email notification that there were 4 replys about the subject, but it's not here anymore.....can not remember his screen name, but if you see this please repost....My question was how many satillite receivers were you using in your plane.
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Old 03-03-2008, 08:26 PM
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Default RE: Glitch when installing carbon fiber prop lost post

Hey it was my post.. I had the standard ar7000 setup one main receiver and one satillite receiver.
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Old 03-03-2008, 09:02 PM
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Default RE: Glitch when installing carbon fiber prop lost post

For those that missed the thread that I had originally I'll do a quick recap.

I have a 33% extra that I flew 3 times yesterday with a wood prop and then I flew it 2 times with a carbon fiber prop. On the second flight with the carbon fiber prop I was bringing the plane around and when the plane was pointing directly at me and the receivers were between the prop and the transmitter it went into failsafe mode. When the prop was no longer directly between the receiver and tx I got control back almost instantly. Batteries were not an issue I was running twin 6v 2700mah nimh packs that were load tested 2 min before the flight. Both the main and satellite receiver are at least 18 inches away from the motor or ignition. The only thing that changed was the prop. I was posting to see if others have had this happen to them before so I could confirm if it was the prop or if I'd just been standing in the sun to long. Funny thing is I’ve had this Radio since they came out. I’ve made hundreds if not a thousand+ flights across 10-15 different airplanes all glitch free. Now the second flight I’ve ever used a CF prop and it goes into failsafe mode. It seems a bit fishy to me.



P.S. Another poster suggested I try and recreate it on the ground. So when the weather gets better here I'm going to try.
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Old 03-03-2008, 09:28 PM
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Default RE: Glitch when installing carbon fiber prop lost post

Thanks for the re-post..... I have never had a problem with changing the prop, but had a problem in the past with a ar9000 receiver just momentarily lost control, but regained it before disaster. 2.4 is somewhat new to me and all ears on suggestions or information that might help me in future installations.
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Old 03-03-2008, 09:41 PM
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Default RE: Glitch when installing carbon fiber prop lost post


ORIGINAL: flynut007

Thanks for the re-post..... I have never had a problem with changing the prop, but had a problem in the past with a ar9000 receiver just momentarily lost control, but regained it before disaster. 2.4 is somewhat new to me and all ears on suggestions or information that might help me in future installations.

No problem Flynut. Going into failsafe mode is a whole new ballgame to me. Talk about flying by the seat of your pants... I do want to figure out exactly what is happening. This plane only has 12-13 flights total on it since I got it going. So I’m not ruling out anything. Also if anyone has any ideas I’m all ears. I may try a different receiver after the ground tests are complete.
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Old 03-03-2008, 10:49 PM
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Default RE: Glitch when installing carbon fiber prop lost post

http://www.rcuniverse.com/forum/fb.asp?m=5823536
http://www.rcuniverse.com/forum/fb.asp?m=5834113

Here is the one data point I personally have on this topic. (Quique's Yak post #29 and 43 in thread linked)

Did some calling for Quique at Top Gun demos, and helped him out.
Had an X9303, AR9000 (w/two remotes), and data logger.

Did a lot of testing (show prep, where he went out of his way to 'try' to get bad data far out, rolling head on, etc.) and demoes with this DA150 aicraft and carbon prop. Great RF link, few fades, and no holds.
(also had twin tuned pipes and metal heat shield in the belly.)

I would reccomend an AR9000, AR9100, or JR equivalent in this kind of application..... Data logger is also very valuable to verify the Rf link with increasingly difficult flight distances and circumstances. Have not failed to get the correct result yet.

Didn't have any problems in this case.... Also flying the AR9000 in my Mig with carbon bypass, tail pipe, turbine, etc.

Just my personal 2 cents FWIW.

Have Fun,
David
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Old 03-03-2008, 11:20 PM
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Default RE: Glitch when installing carbon fiber prop lost post

Thanks for the reply..... are people using the dual receiver set-up in the large airplanes with 2.4 like they were with 72mhz? I have bought 2 921 receivers and extra satellites for both of the main receivers for a 35% pitts.....
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Old 03-04-2008, 10:10 AM
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Default RE: Glitch when installing carbon fiber prop lost post

Hi,

I think people are doing a lot of different things. Quique's used matchboxes to shed some power load of the main Rx... As I recall... One battery powering all (or was it half of?) Aileron Servos, One battery powering all Rudder servos. One powering Rx, and the rest of the servos.

The new 9100 gives a good option for large aicraft (further load isolation work may be needed for extremely large aircraft).

I have not really seen much of the 'dual main Rx boxes' in the SPM world myself.

Some folks use power boxes with success.

Personally, I am leary of regulators in large aircraft unless the user really understands its true continuous capability, and has done some testing on the system. (Sadly I have seen some beautiful large models lost 72 and 2.4 with one or two smaller regulators installed, and the operator thinking he was in good shape.) 8711 class servos are really pretty much in a new class, and need to be considered differently than a traditional 'digital' servo.

FWIW, I tend to make sure the remote Rx's are spread by a pretty good distance... often using longer extensions ( 24-36" ). Make sure they are oreinted differently to cover different planes/axis's. All three axis in larger aircraft.

My personal 2 cents. Hope this helps,
David
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Old 03-04-2008, 10:24 AM
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Default RE: Glitch when installing carbon fiber prop lost post

TxDiveBomber

Simply an another fliers input.

I have great difficulty accepting that it was anything more than coincidence. The reason is that we may visualize a "carbon fiber disk" in fact it has just as many openings as before simply at a different cycle.
RF traveling at the speed of light (a fact) would not be inhibited by a mere 7 to 10,000 rpm carbon fiber blade width. In fact there are far more area in 'openings' than in blade area regardless of the rpm.

Visualize it as a directed beam of light (same speed) pointed at the same prop and rpm.in a darkened room.
Does light get through------you betcha!
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Old 03-04-2008, 11:51 AM
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Default RE: Glitch when installing carbon fiber prop lost post

I'm going to move the receivers around.. I'm also going to buy an extension on the way home from work today and move the sat receiver closer to the tail. I too have a hard time accepting that a prop could be the sole reason this happened. It may have been nothing more than a coincidence like you said Onewasp. If I had hundreds of flights on this bird I may dispute that. However only having 12-13 I could have just turned it at the perfect angle to loose signal when the CF prop was on. One thing I would like to add is I did an extensive range check before I flew this for the first time. I did the check with the motor off turning the plane 360deg then repeated it with the motor running. It passed with literally flying colors. So when it went into failsafe mode in the air I was very surprised to say the least.

I've been a big advocate of the 2.4 systems from the start and it's been my experience that most problems people experience are due to insulation errors. This could be the case with my extra. Since this is my largest flying bird with 2.4 I may need to move the sat receiver further away than the standard 6" extension allows. That may in fact resolve the issue. Anyways thank you all for your input I hope that the suggestions ya'll have provided resolve this.

Happy Landings,

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